KUWAIT (Reuters) - Iraq's oil minister said on Tuesday that the oil market had become more complicated than before and it was difficult to say whether crude prices had reached a bottom.

"In 2015, Brent prices were in the mid-40s (dollars) and we said back then the prices have bottomed and they will go up," Adel Abdel Mahdi told an energy forum in Kuwait City.

"Back then we thought the marginal producers will get out of the market and demand will rise, stocks will drop and prices will increase. But what happened is not what we have hoped for," Mahdi said.

"Now we realize the situation is more complex than what we thought ... There is a struggle, we are all - the producers in OPEC and non-OPEC - underwater. Those who will fight will get out. But we are underwater without oxygen masks."

Mahdi said few OPEC members could continue making profits amid current low oil prices and the cost of production at $10 a barrel.

The minister warned that a continued drop in prices would curtail investments, suggesting that any "rise in oil prices could also be tough and surprising".

(Reporting by Rania El Gamal, editing by Sami Aboudi and Dale Hudson)